An apparatus for packaging articles in deaerated condition is known as disclosed in Japanese Utility Model Application Laid-Open No. 2-43207. This apparatus has an elongate pipe nozzle disposed along a transport path for transporting a multiplicity of articles in a longitudinally aligned condition and connected at one end to a vacuum pump. A belt-like film is tubulated to enclose articles and the pipe nozzle integrally therewith, the tubulated film being then heat sealed between adjacent articles as the air in the tubulated film is sucked by the pipe nozzle.
With this known packaging apparatus, the trouble is that when the air in the tubulated film is a little too vigorously sucked by the nozzle, there will develop a pressure differential relative to the exterior that will cause the film to cling to the pipe nozzle. This causes friction between the nozzle and the film, which will prevent the film and individual articles from advancing further. Therefore, with such a prior art apparatus for packaging articles in deaerated condition, it is necessary that the degree of vacuum be lowered in proportion as the film travels farther, which makes it impracticable to achieve any satisfactory deaeration.